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Light mag. 4.3 earthquake - Bering Sea, 111 mi southwest of Unalaska, Aleutians West, Alaska, USA, on Thursday, Sep 23, 2021 at 11:41 am (GMT -11) -

Light mag. 4.3 earthquake - Bering Sea, 111 mi southwest of Unalaska, Aleutians West, Alaska, USA, on Thursday, Sep 23, 2021 at 11:41 am (GMT -11) Light mag. 4.3 earthquake - Bering Sea, 111 mi southwest of Unalaska, Aleutians West, Alaska, USA, on Thursday, Sep 23, 2021 at 11:41 am (GMT -11)

Light magnitude 4.3 earthquake at 33 km depth

23 Sep 22:55 UTC: First to report: USGS after 14 minutes.
Update Thu, 23 Sep 2021, 23:00

Moderate tremor of magnitude 4.3 just reported 26 miles southeast of Nikolski, Alaska, United States

4.3 quake 23 Sep 11:41 am (GMT -11)
4.3 quake 23 Sep 11:41 am (GMT -11)
A magnitude 4.3 earthquake near Nikolski, Aleutians West, Alaska, USA, was reported only 19 minutes ago by the United States Geological Survey, considered the key international and national agency that monitors seismic activity in the US. The earthquake occurred at a moderately shallow depth of 20 miles beneath the epicenter in the morning on Thursday, September 23rd, 2021, at 11:41 am local time. The exact magnitude, epicenter, and depth of the quake might be revised within the next few hours or minutes as seismologists review data and refine their calculations, or as other agencies issue their report.
Our monitoring service identified a second report from the European-Mediterranean Seismological Centre (EMSC) which listed the quake at magnitude 4.3 as well.
Towns or cities near the epicenter where the quake might have been felt as very weak shaking include Nikolski (pop. 18) located 26 miles from the epicenter.
VolcanoDiscovery will automatically update magnitude and depth if these change and follow up if other significant news about the quake become available. If you're in the area, please send us your experience through our reporting mechanism, either online or via our mobile app. This will help us provide more first-hand updates to anyone around the globe who wants to know more about this quake.

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Earthquake details

Date & timeSep 23, 2021 22:41:09 UTC -
Local time at epicenterThursday, Sep 23, 2021 at 11:41 am (GMT -11)
Depth32.9 km
Epicenter latitude / longitude52.7114°N / 168.3776°W (Bering Sea, Alaska, United States)
Antipode52.711°S / 11.622°E
Shaking intensityWeak shaking near epicenter
Felt0 reports
Primary data sourceUSGS (United States Geological Survey)
Nearest volcanoVsevidof (51 km / 32 mi)
Nearby towns and cities41 km (26 mi) SE of Nikolski (pop: 18) | Show on map | Quakes nearby
178 km (111 mi) SW of Unalaska (pop: 4,490) | Show on map | Quakes nearby
179 km (111 mi) SW of Dutch Harbor (pop: 4,380) | Show on map | Quakes nearby
234 km (145 mi) SW of Akutan (pop: 1,040) | Show on map | Quakes nearby
Weather at epicenter at time of quakeBroken Clouds 8.8°C (48 F), humidity: 54%, wind: 3 m/s (5 kts) from SW
Estimated seismic energy released1.8 x 1011 joules (49.4 megawatt hours, equivalent to 42.5 tons of TNT) | about seismic energy
Show interactive Map
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Data for the same earthquake reported by different agencies

Info: The more agencies report about the same quake and post similar data, the more confidence you can have in the data. It takes normally up to a few hours until earthquake parameters are calculated with near-optimum precision.
4.333 km41 Km SE of Nikolski, AlaskaUSGS
4.740 kmFox Islands, Aleutian IslandsGFZ


Seismic station: Adak, Aleutian Islands, Alaska (ADK/IU network) | Distance from quake: 572 km / 355 mi | Show on map | Station Info
Seismic station Adak, Aleutian Islands, Alaska: vertical movement plot around time of quake (source: IRIS/BUD)
Seismogram (vertical component) around time of quake. Thin dotted red line indicates time of quake. Seismic waves arrive some time later, depending on distance. Source: IRIS Buffer of Uniform Data (BUD) webtool
Show more

User reports for this quake

User reports estimate the perceived ground shaking intensity according to the MMI (Modified Mercalli Intensity) scale.
There are no user reports for this quake.

Earlier earthquakes in the same area

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